Drill



R. D. MADDOX.

DRILLl APPLICATION FILED omar, |913.

Patented June 8, 1920 f I Ja 1 \\-f- 2o ,e5

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MNTTE@ ROBERT D. MADIDOX, 0F THE UNITED STATES ARMY.

DRILL.

intenso.

Specification of Letters Patent.

Patented J une 8, 1920 Application :filed December 31, 1818. Serial No. 269,099.

(FILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. L., 625.)

To all whom t may concern.'

Be it known that l, ROBERT D. MADDOX, major Medical Dept., U. S. Army, a citizen of the United States, stationed at l/Vashington, D. C., have invented an Improvement in Drills, of which the following is a specification.

The invention described herein may be used by the Government, or any of its officers or employees in prosecution of work for the Government, or by any other per son in the United States, without payment of any royalty thereon.

This invention relates to drill devices, more particularly to hand operated drill devices, and commonly known as breast drills which ordinarily includes a supporting han- (lle, a rotative drill supporting member, a plate adapted to be pressed against the person of the operator, and means for rotating the drill supporting or clutch portion of the device.

rlhe principal obj ect of the present invention is to provide a simply constructed device of this character whereby force may be applied longitudinally to the drill, and the drill supporting mechanism retained in position while being operated.

lVith this and other objects in View, the invention consists in certain novel features of construction as hereinafter shown and described and then specifically pointed out in the claims, and in the drawings illustrative of the preferred embodiment of the invention.

Figure 1 is a sectional elevation of the improved device.

Fig. 2 is a side elevation viewed at right angles to the structure shown in Fig. 1.

Fig. 3 is a detached view of the breast plate member.

The improved device comprises a tubular stock or standard 10 in which a stud 11 is rotatively supported in any suitable manner, for instance. by the coaction of an annular channel 12 in the stud to receive a stop pin 13 extending through the standard. By this means the stud is rotative in the standard and held from longitudinal movement therein.

Bearing upon the lower end of the stock 10 is an annular wear ring 15. The chuck7 is indicated as a Vwhole at 16 and is rigidly attached to the stud 11, and surrounding the stud between the wear ring 15, and the body of the chuck is another annular wear member 17 the contiguous faces of the wear members forming seats for bearing balls 18.

Formed through the stock 10 are oppositely disposed longitudinal slots 20-21 to receive the body portion 22 of a shaft, the shaft passing through the slots and threaded at one end as shown at 23 to receive a combined clamping member and handle or holder, 24.

At its ends the slot 20 is enlarged to form seats 25, and the portion of the shaft 22 opposite to the threaded part is enlargedV to form a shoulder as shown at 26, to engage in the seats when the shaft is located at the ends of the slots. Thus when the grip member 24 is released the shaft 22 can be moved endwise until the shoulder is free from the adjacent seat 25. Then the shaft can be moved to the other ends of the slots and the member 24 rotated to draw the shaft endwise again and couple in its new position with the shoulder 26 in the other seat 25.

By this simple arrangement the shaft may be adjusted longitudinally of the stock 10 a distance equal to the lengths of the slots,

and firmly locked in position at eachY terminal of its adjustment by the coaction of the enlargement or shoulder 26 and the seats 25.

Rigidly connected to the shaft 22-26 is a double bevel gear 2728, the shaft having an enlarged head 29 to support the gear.

Rigidly coupled in any suitable manner to the chuck 16 is a double pinion 30-31, adapted to be alternately engaged by the gears 27 or 28 according to the po sition of the shaft 22--26 in its slots 20-21. Thus when the shaft 22-26 islocated at one end of the slots, the larger bevel gear 27 will be disposed in position to engage the pinion 31, and when the shaft is located at the other end of the slots, the smaller bevel gear will be in position to engage with the bevel pinion 30. Thus two speeds may beimparted to the chuck, as will be obvious, by simply changing the adjustments of the parts as above noted.

The tubular standard 10, is extended upwardly and at its upper end is internally threaded as represented at 32 to receive a threaded ,rodI 33 which may thus be adjusted relatively to the standard l0, and Within the range of its threaded portion. Near its upper end the rod 32 is provided With a stop collar 34, and attached to the rod eX- gage over the stop collar 34. The sleeve is provided With a longitudinally directed. rguide slot il, and the standard l0 is proprovided with a guidel pin l2 Which projects into the slot. By this means when the sleeve v is adjusted longitudinally of the standard it is held from rotation relatively thereto. By this simple m'eans pressure may be applied to the drill, and the pressure continued as the drill euts into the member Which Vis being operated upon by simply rotating the Wheel At the same time the drill is held in position and prevented from lateral displacement by the coaetion of the sleeve and the standard. By

iiaisoV locating a centering device above the Wheel 35, any required pressure may be applied to the drill, as will be obvious.

The improved implement may be utilized as an ordinary breast drill by detaehingthe sleeve 39 and the screw 33, together with its attachments, and substituting therefor the usual breast plate represented at 60, in Fig. 3, the latter having a threaded stud 61, to engage ythe threaded seat 32 of the member 10. Y

The improved device is simple in construction, can be inexpensively manufaetured and supplied as an attachment to an ordinary breast drill, or furnished together with the breast drill, as may be preferred.

Having thus described the invention, what is claimed as new is- A drill of the class described, including a tubular stoel; having an internally threaded portion adapted for engagement with the threaded stud of a breast plate, a threaded rod engaging the threaded portion of the stock, a guidel sleeve slidable over the stock and housing the rod, means for locking the sleeve to the stoek and meansrfor rotating the rod to feed the drill.

f ROBERT D. MADDOX. 

